Chuck device for sabre saws

ABSTRACT

A chuck device for sabre saws in which said device includes a chuck block having an aperture with a tapered portion therein, fixedly connected to the outer end of the saw bar which also has a tapered portion that terminates in an end portion of reduced diameter. Connecting means clamp the chuck block on the saw bar to lock the respective tapered portions against each other and prevent turning of the chuck block relative to the saw bar. The saw blade is clamped upon the chuck block in an offset position from the axis of the saw bar.

United States Patent [191 Batson [451 Mar. 12, 1974 CHUCK DEVICE FORSABRE SAWS Primary ExaminerDonald R. Schran t A. B P k [75] [men orWilliam son, [C ens S C Attorney, Agent, or FirmMarshall J. Breen;Chester Assigneel The Singer p y, e York, A. Williams, Jr.; HaroldWeinstein NY. 22 Filed: Nov. 29, 1972 [571 ABSTRAQT A chuck device forsabre saws in which said device in- [211 App]' 310304 cludes a chuckblock having an aperture with a tapered portion therein, fixedlyconnected to the outer 52 us. Cl 30/394, 83/699, 83/747 n of the saw barwhich also has a tapered portion [51] Int. Cl B27b 19/08 that terminatesin n n p rtion f r duced diameter. [58] Field of Search 30/392, 394;83/747, 699, Connecting means clamp the chuck block on the saw 83/697,v698 bar to lock the respective tapered portions against each other andprevent turning of the chuck block rel- [56] R f es Cit d ative to thesaw bar. The saw blade is clamped upon UNITED STATES PATENTS the chuckblock in an offset position from the axis of the saw bar. 1,502,0887/l924 Colby 30/394 3,547,166 l2/l970 Dudek 83/699 5 Claims, 4 DrawingFigures lll lll Q t; 68 7o 70 44 1. .2:

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CHUCK DEVICE FOR SABRE SAWS BACKGROUND OF THE INVENTION Heretofore, thesabre saws of the prior art have used chucks connected to the outwardlyextending end of the saw bar by means of pins or a plurality of setscrews.

SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to provide an improved chuck device for sabre saws; which issimple, economical and reliable; which overcomes the prior artdisadvantages; which has a tapered interconnection between the saw barand chuck; which provides a positive mechanical connection between thesaw bar and chuck device; which has the saw blade connected to the chuckoffset from the axis of the saw bar; and which is locked in angularposition with respect to the saw bar.

Other objects and advantages will be apparent from the followingdescription of one embodiment of the invention, and the novel featureswill be particularly pointed out hereinafter in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS This invention is illustrated in theaccompanying drawings in which:

FIG. 1 is a longitudinal, elevational view, partly in section, of asabre saw embodying the present invention.

FIG. 2 is an exploded perspective view, partly in section, showing theimproved chuck device of the present invention.

FIG. 3 is a bottom plan view taken along line 3-3 of FIG. 1.

FIG. 4 is an elevational view, partly in section, taken along line 4-4of FIG. 3.

DESCRIPTION OF THE INVENTION Referring now to FIG. 1 of the illustratedembodimentof the invention, a shaft of a driving electric motor 12mounted in a housing 14, extends into a gear housing 16 and is formedwith a splined portion 18 which meshes with and drives a gear 20journaled in the gear housing 16. The gear 20 carries an eccentric pin22 surmounted by a roller 24 which engages the slide portion of acrosshead 26. The crosshead 26 has a central transverse opening 28 incommunication with the slide portion. A pair of aligned holes 30 areformed in the top and bottom of the crosshead 26 perpendicular to thetransverse opening 28 of a circular diameter just slightly larger thanthe cross-sectional diameter of a saw bar 32 which extends therethrough.The saw bar 32 is free to turn' about its axis within the hole 30 of thecrosshead 26, but is held axially captive by an annular collar 34exposed in the opening 28 and affixed to the saw bar 32 by a split pin36, as illustrated in FIG. 1. The saw bar 32 is journaled for linearmovement in a sleeve bearing 38 secured in the bottom portion of thegear housing cover 40, and a journal bushing 42secured in the top 44 ofthe combined gear housing 16 and the gear housing cover 40. A gear 46journaled in the gear housing 16 meshes with gear 20 and by means of aneccentric pin 48 and roller 50, drives an upper balancing crosshead 52which is free to turn and slide on the saw bar 32.

Upon operation of the sabre saw, the motor shaft 10 will drive the gear20 which, through pin 22 and roller 24 working in crosshead 26,transmits linear axial reciprocatory motion to the saw bar 32 and drivesan affixed saw blade 54 having a cutting edge 56 in a linearreciprocatory path substantially normal to the plane of a workcontacting shoe 58.

The saw blade 54 is affixed to the saw bar 32 by an improved chuckdevice designated generally 60, which serves to interconnect the sawblade 54 and the saw bar The journal bushing 42 is connected to acontrol knob 62, which when in unlocked position, may be rotated by theoperator to control the angular position of the saw bar 32 and the saw.blade 54. The saw bar 32 is free to reciprocate within the journalbushing 42, but is interconnected by a pin 64 which reciprocates withina slot 66 formed in the journal bushing 42. Thus, turning of the journalbushing 42 will turn the saw bar 32 through the trapped pin 64. Further,the journal bush ing 42 has a flange 68, the outer periphery of which,has angularly disposed slots 70 circumferentially spaced thereabout. Thecontrol knob 62 may be locked in non-turnable position by inserting aslide switch 72 within one of the slots 70. Removal of the slide switch72 from the slot 70 permits operator turning of the control knob 62 andinterconnected saw bar 32 and saw blade 54. The slide switch 72 ismounted in the upper portion of a handle 74 which is secured to the gearhousing 16 in superposition to and cantilevered over the motor 12, andcarries a conventional trigger switch 76 and associated lock button 78on the underside thereof for actuating the motor 12 in the usual manner.The slide switch 72 is slidably mounted within the handle 74intermediate the trigger switch 76 and the control knob 72.

The improved chuck device 60 is shown best in FIGS. 2 and 4 and includesa chuck block 80 having a vertical blade aperture 82 extending throughthe chuck block on one side thereof, with a transverse pin 84 extendingacross its upper end. Below the pin 84, a tapped hole 86 communicateswith the aperture 82 to receive a blade locking screw 88, so that whenthe saw blade 54 is disposed into the aperture 82, it will abut the pin84 prior to the screw 88 being tightened to clamp the blade 54 withinthe aperture 82 of the chuck block 80. The blade aperture 82 is offsetfrom theaxis 90 of the saw bar 32 by being spaced from a counterboredaper- 4 ture or hole 92 to which the saw bar 32 is connected. Thevertical counterbored hole 92 is formed on the other side of the chuckbook 80 with the smallest opening 94 facing the bottom. The upper end ofthe counterbored hole 92 is tapered as at 96 to flare outwardly asillustrated in FIG. 2. A tapped hole 98 is formed in the front of thechuck block 80 to communicate with the counterbored hole 92 intermediatethe bottom opening 94 and the tapered portion 96. A set screw 100 isthreadedly received in the tapped hole 98 as illustrated in FIGS. 2, 3and 4, for purposes more fully explained hereinafter.

The saw bar 32 has an outer end 102 which extends below the sleevebearing 38. A tapered section 104 is formed on the outer end upwardlyfrom the bottom to slope downwardly and inwardly. An annular groove 106is formed below the tapered section 104. An end section 108 of adiameter smaller than the diameter of the saw bar 32 but of largercross-sectional area than the annular groove 106, is formed at thebottom of the saw bar 32. A tapped hole 1 extends axially upwardly fromthe bottom of the saw bar, as best seen in FIG. 4. The outer end 102 ofthe saw bar 32 from the tapered section downwardly, is sized to matewithin the counterbored hole 92 of the chuck block 80 in which positionthe annular groove 106 will be placed in alignment with the tapped hole98. The tapered section 96 and 104 respectively, are sloped tocorrespond to each other. Upon the outer end 102 of the saw bar 32 beinginserted into the counterbored hole 92 of the chuck block 80, a lockingscrew 112 will be threadedly received in the tapped hole 110 to lock thechuck block 80 to the saw bar 32. The set screw 100 will be threadedagainst the angular groove 106 to lock the chuck block 80 in desiredposition and prevent angular movement with respect to the saw bar 32.This provides for a positive mechanical connection by means of thescrews 100 and l 12, to the outer end 102 of the saw bar 32 in differentplanes, while the frictional contact of the mating tapered sectionssecurely clamps the chuck block 80 relative the saw bar 32. The offsetmounting of the saw blade 54 to the chuck device 60 is advantageousduring both straight cutting and further provides a mechanical advantageduring scroll or free form cutting;

It wll be understood that various changes in the details, materials,arrangements of parts and operating conditions, which have been hereindescribed and illustrated in order to explain the nature of theinvention, may be made by those skilled in the art within the principlesand scope of the invention.

Iclaim:

l. A sabre saw for driving a saw blade comprising:

a. a housing,

b. a motor mounted in the housing,

0. a saw bar journaled in the housing and drivingly connected to themotor to be reciprocated along a linear axis,

d. the saw bar having an outer end extending from the-housing,

e. the outer end having a tapered portion terminating in an end portionof reduced diameter,

f. a chuck means having an aperture with a tapered portion thereindisposed upon the outer end of the saw bar,

g. connecting means clamping the chuck means upon the saw bar to lockthe respective tapered portions against each other and to preventturning of the chuck means relative the saw bar, and

h. means clamping the saw blade upon the chuck means offset from theaxis of the saw bar.

2. The combination claimed in claim 1 wherein:

a. the connecting means including an axially extending tapped holeformed in the bottom of the saw bar and a screw passing into theaperture of the chuck means to be threadedly received in the tapped holeand to force the respective tapered portions into clamped engagementwith each other.

3. The combination claimed in claim 2 wherein:

a. the connecting means including means to prevent turning of the chuckmeans and saw bar relative each other.

4. The combination claimed in claim 3 wherein:

a. a tapped hole formed in the chuck means in communication with theaperture and below the tapered portion;

b. a set screw threadedly received in the tapped hole to engage and lockthe saw bar and the chuck means from relative rotation.

5. A sabre saw for driving a saw blade comprising:

a. a housing,

b. a motor mounted in the housing,

c. a saw bar journaled in the housing and drivingly connected to themotor to be reciprocated along a linear axis,

d. the saw bar having an outer end extending from the housing,

e. the outer end having a tapered portion terminating in an end portionof reduced diameter, f. a tapped hole formed in the bottom of the sawbar to extend upwardly in the axial direction,

g. a chuck block having a blade slot on one side and an aperture on theother side,

h. a taper portion formed in the aperture corresponding to the taperedportion of the outer end of the saw bar,

i. a screw connected in the tapped hole to force the corresponding taperportions against one another to lock the chuck block upon the saw bar,and

j. means interconnecting the chuck block and the saw bar to preventturning of the chuck block relative the saw bar, and

k. means connecting the saw blade within the blade slot.

1. A sabre saw for driving a saw blade comprising: a. a housing, b. amotor mounted in the housing, c. a saw bar journaled in the housing anddrivingly connected to the motor to be reciprocated along a linear axis,d. the saw bar having an outer end extending from the housing, e. theouter end having a tapered portion terminating in an end portion ofreduced diameter, f. a chuck means having an aperture with a taperedportion therein disposed upon the outer end of the saw bar, g.connecting means clamping the chuck means upon the saw bar to lock therespective tapered portions against each other and to prevent turning ofthe chuck means relative the saw bar, and h. means clamping the sawblade upon the chuck means offset from the axis of the saw bar.
 2. Thecombination claimed in claim 1 wherein: a. the connecting meansincluding an axially extending tapped hole formed in the bottom of thesaw bar and a screw passing into the aperture of the chuck means to bethreadedly received in the tapped hole and to force the respectivetapered portions into clamped engagement with each other.
 3. Thecombination claimed in claim 2 wherein: a. the connecting meansincluding means to prevent turning of the chuck means and saw barrelative each other.
 4. The combination claimed in claim 3 wherein: a. atapped hole formed in the chuck means in communication with the apertureand below the tapered portion; b. a set screw threadedly received in thetapped hole to engage and lock the saw bar and the chuck means fromrelative rotation.
 5. A sabre saw for driving a saw blade comprising: a.a housing, b. a motor mounted in the housing, c. a saw bar journaled inthe housing and drivingly connected to the motor to be reciprocatedalong a linear axis, d. the saw bar having an outer end extending fromthe housing, e. the outer end having a tapered portion terminating in anend portion of reduced diameter, f. a tapped hole formed in the bottomof the saw bar to extend upwardly in the axial direction, g. a chuckblock having a blade slot on one side and an aperture on the other side,h. a taper portion formed in the aperture corresponding to the taperedportion of the outer end of the saw bar, i. a screw connected in thetapped hole to force the corresponding taper portions against oneanother to lock the chuck block upon the saw bar, and j. meansinterconnecting the chuck block and the saw bar to prevent turning ofthe chuck block relative the saw bar, and k. means connecting the sawblade within the blade slot.